Endoscopic surgical stapler with compact profile

ABSTRACT

A surgical stapler having an end effector with a reduced stacking height for its components to decrease the diameter of a trocar cannula or other access device during minimally invasive surgery is disclosed. The end effector includes an elongated channel containing a staple cartridge and an anvil movable toward and away from the channel. The anvil is movable to first, second and third fixed positions relative to the channel. The first fixed position is a closed position which eliminates clearance between the anvil and cartridge. The second fixed position is an open position for inserting tissue between the anvil and cartridge. The third fixed position is a clamped position where a tissue-clamping gap exists between the anvil and cartridge to properly clamp tissue. The elimination of clearance between the anvil and cartridge of the first fixed position of the anvil reduces the stacking height, and therefore enables the user to insert the stapler through a smaller diameter access opening.

BACKGROUND OF THE INVENTION

This invention relates to surgical instruments for performing endoscopicprocedures. More particularly, it relates to endoscopic surgicalstaplers which have a compact configuration particularly adapted forminimally invasive surgical procedures.

During an endoscopic surgical procedure, access to the surgical sitewithin the body cavity is provided through openings of a small diametermade in the body wall. An instrument frequently used to provide thisaccess is the trocar. The trocar is an assembly which includes anobturator and a cannula. The obturator has a sharp tip which is used topuncture the body wall to provide the access opening. The obturatorslides within the cannula, which is a hollow, cylindrical sleeve. Whenthe obturator has punctured the body wall, the obturator is removed fromthe cannula. The cannula, however, remains in place within the openingmade in the body wall by the obturator. Consequently, the cannulaprovides a cylindrical passageway to gain access to the surgical sitewithin the body cavity.

Accordingly, a characteristic feature of many endoscopic surgicalinstruments is a long cylindrical shaft which can slide through thetrocar cannula. At the business end of the shaft, which is the end ofthe instrument coming into contact with tissue at the surgical sitewithin the body cavity, an "end effector" is provided to manipulate thetissue in some way to carry out a desired surgical procedure. Thebusiness end, including the end effector, must likewise be capable ofsliding through the trocar cannula.

In most cases, it is the end effector which dictates the size of thecylindrical shaft. The cylindrical shaft is typically sized to have across-sectional diameter large enough to house the combination ofcomponents of the end effector.

One particularly desired function of an end effector of an endoscopicsurgical instrument is the ability of the end effector to fire staplesinto bodily tissue for fastening the tissue. In some procedures, it isdesirable to first clamp the tissue so that the clamped tissue may befastened when staples are fired into and through the tissue. Instrumentswith end effectors which fire staples into clamped tissue are referredas linear staplers and cutters (cutters are so named because theysimultaneously cut the tissue with a knife between rows of firedstaples).

The end effector of a linear stapler or cutter typically has twoopposed, elongated jaws. The jaws have internal tissue-contactingsurfaces between which the tissue is clamped. The jaws are oftendescribed as a lower jaw and an upper jaw. The lower and upper jaws moverelative to each other. When the jaws are moved to an open position, thetissue-clamping surfaces of the jaws are spaced from each other so thattissue can be placed between the two surfaces. When the jaws are movedto their closed position, the tissue-contacting surfaces of the jaws arepositioned adjacent each other so that the tissue placed between thejaws is clamped.

Linear cutters and staplers have conventionally had a fixed lower jawand a pivoting upper jaw which pivots from an open to a closed positionrelative to the lower jaw. The fixed lower jaw may include a channel forreceiving a staple cartridge. The upper jaw typically includes an anvil.Accordingly, when a linear stapler or cutter is used, tissue is placedbetween the tissue and anvil. When the upper jaw is placed in the openposition, the upper jaw is pivoted to its closed position to clamptissue between the cartridge and anvil, and staples are subsequentlyfired from the cartridge into the clamped tissue for formation againstthe anvil.

Since the cylindrical shaft of an endoscopic linear stapler or cuttermust be sized to house the components of the end effector, it is the endeffector which therefore dictates the size of the endoscopic portion ofthe instrument. Therefore, the end effector also controls the size ofthe trocar which is used to provide access to the surgical site withinthe body cavity. Accordingly, it has always been a desired goal ofengineers and designers in the field of endoscopic surgicalinstrumentation to effectively reduce the overall size of the endeffector to in turn minimize the size of the trocar which is needed toprovide access into the body.

The overall "size" of the end effector of a linear stapler or cutter isgoverned by the number of components which make up the end effector andthe clearances which are necessary between the components. The criticalsize parameters which dictate the diameter of the cylindrical shaft ofthe instrument are the stacking height of each of the components of theend effector and the extent to which the components must be spaced fromeach other. Obviously, the overall size of the end effector can bereduced if the components of the end effector can be tightly"sandwiched" together to minimize the stacking height.

In connection with the endoscopic stapler or cutter, the stackedcomponents of the end effector include the lower and upper jaws, and thestaple cartridge received within the lower jaw. In addition, a clearancehas conventionally been provided between the lower and upper jaws toaccount for the ability to place tissue between the jaws for clamping.It is these stacked components and the clearance between the upper andlower jaws which in turn define the size of the cylindrical shaft of theinstrument. While the size of the cylindrical shaft and therefore theendoscopic portion of linear staplers and cutters has been acceptable,there has been and will continue to be a push for effectively smallerinstruments.

Accordingly, the surgical community would benefit from a change in thedesign of the end effector of an endoscopic surgical stapler which wouldreduce the stacking height of the end effector. Such a reduction in thestacking height would enable the use of an instrument with an endoscopicportion having a cylindrical shaft of a diameter smaller than that whichhas been previously been used or described in the literature. In thisway, the size of the trocar providing access to the endoscopic surgicalsite can likewise be reduced. Ultimately, the endoscopic procedure canindeed become more minimally invasive because the size of the openingsmade through the body wall can be reduced.

SUMMARY OF THE INVENTION

The invention is an endoscopic surgical stapler which is capable ofclamping bodily tissue prior to firing staples to fasten the tissue. Thestapler comprises an end effector which includes an anvil and anelongated channel. The channel contains a staple cartridge. The anvilfaces the channel, and it is movable toward and away from the channel.

The anvil is movable to first, second and third fixed positions relativeto the channel. The first fixed position is a closed position in whichthe anvil is in intimate contact with the staple cartridge. Thiscontacting position eliminates any clearance between the anvil andcartridge. The second fixed position is an open position in which theanvil is spaced from the cartridge for subsequent clamping. In the openposition, bodily tissue can be inserted between the anvil and cartridgefor subsequent clamping. The third fixed position is a clamped positionin which the anvil is adjacent the cartridge. In the clamped position,there is a tissue-clamping gap between the anvil and cartridge to enablethe bodily tissue to be properly clamped between the anvil andcartridge.

Significantly, the existence of the first fixed position of the anvil onthe end effector of the surgical stapler of this invention provides forthe lowest stacking height obtainable for a stapler which contains acartridge-filled channel and an opposed, movable anvil. The stackingheight is optimized because the clearance conventionally associated withthe tissue gap between the anvil and cartridge has been eliminated.Accordingly, it becomes possible to insert the stapler through a trocarcannula having a smaller diameter because the stacking height of the endeffector of the stapler has been optimized. Of course, this attendantbenefit of the stapler is a highly desirable attribute forinstrumentation designed for minimally invasive surgical applications.

During a minimally invasive surgical procedure, where access to thesurgical site is provided through tubular cannulas of small diameter,the stapler of this invention is initially adjusted so that the anvil onthe end effector is moved to its first fixed position relative to thechannel. Since the clearance between the anvil and cartridge iseliminated to lessen the stacking height of the end effector, a cannulahaving a diameter smaller than that of a conventional cannula can beused to provide access to the site. With the anvil in its first fixedposition, the end effector is inserted through the cannula andpositioned adjacent the bodily tissue to be clamped. Once properlypositioned, the end effector is adjusted to move the anvil from thefirst to second fixed positions relative to the channel. In the secondfixed position, the anvil is spaced from the cartridge, and the bodilytissue can be readily inserted between the cartridge and anvil. When thetissue is inserted, the end effector is again adjusted to move the anvilfrom its second to third fixed positions. In its third fixed position,the anvil has moved to a position adjacent the cartridge, and the tissueis clamped between the cartridge and anvil with a clinically acceptabletissue-clamping gap between the cartridge and anvil. At this point, thestaples can then be fired from the cartridge for formation on the anvilto fasten the clamped tissue. Once the staples have been fired, theanvil is moved from its third to second fixed positions to remove theend effector from the fastened tissue. The anvil is then moved to thefirst fixed position so that the end effector can be readily withdrawnfrom the trocar cannula.

The endoscopic surgical stapler of this invention can be used during anyminimally invasive surgical applications, especially those where it isdesired to further minimize trauma to the patient by continuing toreduce the diameter of trocar cannulas and other access devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation of an endoscopic linear cutter of thisinvention, with one half of the frame subassembly removed to exposeinterior components.

FIG. 2 is the end effector of FIG. 1 where the anvil is in its firstfixed position relative to the channel.

FIG. 3 is a section generally taken along line 3--3 of FIG. 2.

FIG. 4 is a partial side elevation view of the end effector where theanvil is in its third fixed position relative to the channel.

FIG. 5 is a section generally taken along line 5--5 of FIG. 4.

FIG. 6 is a fragmentary side elevation view of an alternative embodimentof the end effector.

FIG. 7 is a fragmentary side elevation view of the embodiment of the endeffector illustrated in FIG. 6 clamped on tissue.

FIG. 8 is a fragmentary side elevation view of yet another alternativeembodiment of the end effector.

FIG. 9 is a fragmentary side elevation view of a further alternativeembodiment of the end effector.

FIG. 10 is a section view generally taken along line 10--10 of FIG. 9.

FIG. 11 is the section of FIG. 10 with the closure sleeve rotated 90°relative to the rotationally fixed components of the end effector.

FIG. 12 is a fragmentary side elevation view of another alternativeembodiment of the end effector where the anvil is in its second fixedposition relative to the channel.

FIG. 13 is the end effector of FIG. 12 where the anvil is in its thirdfixed position relative to the channel.

FIG. 14 is the end effector of FIG. 12 where the anvil is in its firstfixed position relative to the channel.

FIG. 15 is a fragmentary side elevation of the components inside theframe subassembly which enable actuation of the end effector depicted inFIGS. 12-14.

FIG. 16 is a side elevation view of the improved mechanism for movingthe anvil from its second to third positions, which is described incommonly assigned, pending application Ser. No. 08/530,931, filed Sep.19, 1995.

FIG. 17 is a fragmentary side elevation view of a modification of theend effector depicted in FIG. 16 which enables the anvil to move fromits third to first fixed positions.

FIG. 18 is a fragmentary side elevation view illustrating the modifiedend effector depicted in FIG. 17 where the anvil is in its first fixedposition relative to the channel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a surgical stapler 20 which is capable ofpracticing the unique benefits of this invention is illustrated. Thestapler has a frame 21 (the frame is a subassembly consisting of bottomand top halves, and the top half has been removed to depict thecomponents housed inside the frame), a closure sleeve 22 extending fromthe frame, and an end effector 23 extending from the distal end of theclosure sleeve. The end effector includes an elongated channel 24 forreceiving a staple cartridge 25. It also includes a movable anvil 26facing the cartridge upon which the staples from the cartridge areformed.

The frame 21 has a palm grip handle 27 and clamping and firing triggers28 and 29, respectively, pivotally mounted to the frame. The stapler isshown in FIG. 1 with the anvil spaced from the cartridge. Bodily tissue(not shown) can be inserted between the cartridge and anvil. The usergrips the frame with the palm grip handle and squeezes the clampingtrigger against the palm grip handle. In so doing, a pinion 30 with aset of gear teeth 31 drives a gear rack 32 forwardly. The gear rack isattached to an actuator 33, and the actuator is fixed to the closuresleeve 22. Consequently, the closure tube moves from rearward to forwardpositions, and causes the anvil to move from its position spaced fromthe cartridge to a clamping position. When the clamping trigger is fullyactuated and the bodily tissue is clamped, the firing trigger can thenbe squeezed to fire the staples against the anvil to fasten the tissue.A more detailed description of the components of the frame and theirinteraction with the clamping and firing mechanisms of an endoscopiclinear cutter are described in commonly assigned, copending applicationSer. No. 08/191,142, filed Mar. 18, 1994.

Referring to FIGS. 2 and 3, the minimum stacking height of the endeffector is illustrated. The anvil 26 lies flush against the cartridge25, and there is no gap between the anvil and cartridge. The diameter ofthe sleeve can therefore be sized to snugly fit the elongated channeland anvil, and it is unnecessary to increase the diameter to allow forthe conventional gap between the anvil and cartridge fortissue-clamping.

Referring to FIGS. 4 and 5, bodily tissue 34 has been inserted betweenthe anvil and staple cartridge. The anvil is positioned adjacent thecartridge, and a tissue-clamping gap is displayed between the anvil andcartridge. In order for the sleeve to accommodate the clearancenecessitated by the tissue-clamping gap, the distal end of the sleeve ismade to be expandable so that it will deform to appropriatelyaccommodate the stacking height of the end effector components,including the conventional tissue-clamping gap 35. The sleeve can bemade of a thin-walled, metal tube or a polymer which elongates into anon-circular shape to accommodate the increased height of theend-effector.

The alternative embodiments of FIGS. 6-8 illustrate different ways inwhich the distal end of the closure sleeve can be made to expand toallow for the tissue-clamping gap 35 when tissue is clamped between theanvil and cartridge. As illustrated in FIG. 6, a serpentine slot 36 isprovided on either one or both sides of the distal end of the closuresleeve 22. The incorporation of the slot enables the expansion of thedistal end of the sleeve. When the sleeve expands, as depicted in FIG.7, a plurality of "locking points" 37 firmly secure the distal end ofthe sleeve in its expanded condition for tissue clamping. The preciselocation of the locking points dictates the degree of expansion of thesleeve, and therefore the clamping force applied to the end effectorwhen loaded with tissue. FIG. 8 as well illustrates a serpentine slot 36displayed at the distal end of the closure sleeve.

Turning now to FIGS. 9-11, the closure sleeve 22 is used in combinationwith the anvil to provide movement of the anvil from a position allowingfor the tissue-clamping gap 34 and another position where thetissue-clamping gap has been eliminated. The distal end of the rigidclosure sleeve has a pair of swaged, mutually opposed indentations 38.The diameter of the sleeve is sized to accommodate the clearances forthe cartridge-filled channel, anvil and tissue-clamping gap. When theclosure sleeve is rotated 90° to position the swaged indentations intocontact with the channel and anvil, the indentations urge the anvil tosit flush with the staple cartridge in the channel to eliminate theclearance provided by the tissue-clamping gap.

Referring to FIGS. 12-14, the closure sleeve is used in combination witha ramped, cambered anvil to provide the mechanism for moving the anvilinto the three desired fixed positions relative to the channel of theend effector. "Camber" refers to the bend or bow in the anvil to allowits distal end to initially contact the cartridge prior to the remainingportion of the anvil to preload the anvil during closure. The anvil hasa first proximal ramped surface 39 immediately adjacent the distal endof the closure sleeve when the closure sleeve is in its rearwardposition. Extending from the first ramped surface is a second rampedsurface 40. The second ramped surface is steeper than the first rampedsurface. The proximal end of the anvil is fixed to an anvil pivot pin41, and the pin sits in a retention slot 42 in the channel. When theclosure sleeve moves from its rearward position forwardly to anintermediate position as illustrated in FIG. 13, the anvilcorrespondingly moves downwardly from a position spaced from thecartridge to a position adjacent to the cartridge where a clearancebetween the two components is maintained for proper tissue clamping.When the closure tube is further moved forwardly from its intermediateposition to its forwardmost position as depicted in FIG. 14, it slideson the second ramped surface and applies further downward pressureagainst the anvil to eliminate the clearance.

Referring now to FIG. 15, as the clamping trigger 28 is initiallysqueezed to move the closure sleeve from its rearward position to itsintermediate position as illustrated in FIGS. 12 and 13, the upper latcharm 43 of the latch assembly 44 in the frame will slide into a firstdetent 45. An audible and tactile setting can be provided in cooperationwith the thumb release 46 of the latch assembly when the upper latch armmoves into the first detent position to enable the user to know that theanvil is positioned relative to the cartridge in the manner depicted inFIG. 13. As the clamping trigger is further squeezed, the upper latcharm will move onto the second detent 47. Again, an audible and tactilesetting can be provided to inform the user that he has positioned theanvil flush with the cartridge to eliminate the clearance between thecartridge and anvil as depicted in FIG. 14.

Lastly, FIG. 16, in combination with FIGS. 17 and 18, provides anotheralternative embodiment for adjusting the movement of the anvil toprovide three fixed positions relative to the channel of the endeffector. As illustrated in FIG. 16, the channel may contain a generallydiagonal slot 48 for movement of a slot post 49 which is affixed to theanvil 26. As the slot post rides up and down within the channel slot,the anvil correspondingly moves toward and away from the channel. Adetailed description of this closure mechanism is provided in commonlyassigned, copending application Ser. No. 08/530,931, filed Sep. 19,1995. The modification which enables the positioning of the anvil tosubstantially eliminate the conventional clearance between the cartridgeand anvil is shown in FIGS. 17 and 18. Specifically, the anvil isprovided with a ramped surface 50, and a closure member 51 is providedto slide on the ramped surface. When the slot post affixed to the anvilhas ridden to its forwardmost position to position the anvil adjacentthe cartridge, the closure member slides on the ramped surface.Consequently, the anvil is further urged forwardly to eliminate thetissue-clamping gap. Further facilitating the capability of the closuremember to force the anvil flush against the staple cartridge, thechannel is provided with a channel release 52 upon which an anvil slidepin 53 can rest to enable proper alignment of the entire anvil acrossthe staple cartridge.

Although this invention has been described in connection with its mostpreferred embodiment, numerous additional embodiments are readilyenvisioned by those skilled in the art and therefore fall within thescope and spirit of the claimed invention. Accordingly, the preferredembodiments described in the specification are merely intended to beexemplary to provide a clearer understanding of the nature of theinvention, and should not be construed in any way to limit the scope ofthe invention.

What is claimed is:
 1. An endoscopic surgical stapler capable ofclamping bodily tissue prior to firing staples to fasten said tissue,said stapler comprising:an end effector including an anvil and anelongated channel containing a staple cartridge therein, said anvilfacing said channel and movable toward and away therefrom; and arotatable closure sleeve from which said end effector extends, saidsleeve having a pair of mutually opposed indentations; wherein saidanvil is moveable to first, second and third fixed positions relative tosaid channel, said first fixed position being a closed position whereinsaid anvil is in intimate contact with said staple cartridge therebyeliminating any clearance therebetween, said second fixed position beingan open position wherein said anvil is spaced from said cartridge forinserting said bodily tissue therebetween, said third fixed positionbeing a clamped position wherein said anvil is adjacent said cartridgeso as to provide a tissue-clamping gap therebetween for clamping saidbodily tissue, and said anvil is moveable from said third to first fixedpositions when said closure sleeve is rotated and said indentationscontact said anvil and said channel.